1. Field of the Invention
The present invention relates to a gas-line system for a semiconductor-manufacturing apparatus, and it particularly relates to a gas flow-divider used for a gas-line system for single-wafer-processing type semiconductor-manufacturing apparatus and a method for using the same.
2. Description of the Related Art
Conventionally, for a substrate-processing apparatus, there is a single-wafer-processing type and a batch-processing type. With the single-wafer-processing type, a single reactor processes one wafer at a time. With the batch-processing type, a single reactor processes multiple wafers at a time.
Because a batch-processing type processes multiple wafers in a single reactor, its productivity is high. With batch processing, however, the thickness and quality of a thin film formed on a substrate are not uniform and this often becomes a problem. To improve quality and the uniformity of film thickness, use of a conventional single-wafer-processing type substrate processing apparatus is effective. In the case of a conventional single-wafer-processing type substrate-processing apparatus in which multiple reactors are installed with a common transfer chamber, each reactor independently possesses a gas line and a vacuum line and independently performs deposition.
If attempting to increase productivity using a conventional single-wafer-processing type substrate-processing apparatus, the number of reactors increases and the same number of vacuum elements including gas lines and vacuum pumps becomes necessary. As a result, costs per reactor increase and the footprint increases at the same time.
Furthermore, conventionally, for a method for dividing a gas flow into two reactors from one gas line, there is a method using a T-shaped joint. In this case, however, there is a drawback that a gas excessively flows into a reactor having lower pressure. As a result, distribution balance is lost and consequently process balance between two reactors worsens.
Therefore, an object of the present invention is to provide a gas-line system realizing low costs and a small footprint.
Another object of the present invention is to provide a gas-line system which promotes labor saving for gas lines and exhaust lines.
Yet another object of the present invention is to provide a gas-line system realizing stable processing and high throughput and a method for using the same.
To achieve the above-mentioned objects, a gas-line system for a semiconductor-manufacturing apparatus according to the present invention may comprise the following embodiments:
The present invention includes various aspects. For example, in an embodiment, the gas-line system comprises: (a) a source gas line derived from at least one gas source; (b) at least two branch gas lines leading to the respective reactors; and (c) a flow divider for equally distributing the gas passing through the source gas line into each branch gas line, said flow divider comprising (i) an input port connected to the source gas line wherein a gas passes therethrough at a primary side flow rate, and (ii) at least two output ports connected to the respective branch gas lines wherein a gas passes through each branch gas line at a secondary side flow rate.
Although the flow controller does not detect the primary side flow rate, by using the flow meter, the primary side flow rate is detected and a signal corresponding to one half of the flow rate (if two reactors are used) is outputted to each flow controller, instantly balancing the flow rate on the secondary side between the branch source gas lines at a maximum level. Accordingly, using such a simple structure, the total of the secondary side flows can be equal to the primary side flow while equally diverting the primary side flow into each secondary side flow.
In the above the signal of the primary side flow rate and the signal of the secondary side flow rate can either be analog signals or digital signals.
In the above, the flow divider may comprise: (I) at least two flow controllers for setting the respective secondary side flow rates, disposed at the respective output ports: (II) a flow meter for detecting the primary side flow rate, disposed at the input port; and (III) a signal processor for receiving a signal of the primary side flow rate from the flow meter and outputting a signal of the secondary side flow rate to each flow controller to equally set each secondary side flow rate.
In another embodiment, the gas-line system may comprise: (i) a source gas line derived from at least one gas source; (ii) at least two branch gas lines leading to the respective reactors; (iii) a diverging point where the branch gas lines branch off from the source gas line; (iv) a flow rate detecting device provided on the source gas line; (v) at least two flow rate adjusting devices provided on the respective branch gas lines; and (vi) a controlling device which sets a setpoint of each flow rate adjusting device based on a signal from the flow rate detecting device to equally distribute a gas passing through the source gas line into each branch gas line. In the above, the flow rate detecting device may be a mass flow meter, the flow rate adjusting device may be a mass flow controller, and the controlling device may be a signal processor.
In the above, at least two gas sources may be connected to the source gas line, wherein said system further comprises at least two origin source gas lines connecting between the respective gas sources and the source gas line, and a merging point where the origin source gas lines merge into the source gas line.
Additionally, the gas-line system may further comprise an exhaust pump for exhausting each reactor, disposed downstream of the reactors, wherein a pressure control valve is provided between each reactor and the exhaust pump to control gas flow of each reactor.
According to another aspect of the present invention, a method is provided for equally distributing a source gas into at least two reactors for semiconductor processing. The method comprises the steps of: (i) detecting the flow rate of the source gas derived from a gas source; (ii) calculating an equally divided flow rate for the respective reactors; (iii) diverging the source gas into each reactor; and (iv) setting a flow rate between the diverging point and each reactor at the equally divided flow rate.
In the above, the method may further comprise controlling the pressure of each reactor by a single exhaust pump and a pressure control valve provided between each reactor and the exhaust pump.
Further, in the above, the detected flow rate of the source gas may be processed into an analog signal which is used to calculate the equally divided flow rate, and based on an analog signal of the equally divided flow rate, the flow rate is set downstream of the diverging point. Alternatively, the detected flow rate of the source gas may be processed into a digital signal which is used to calculate the equally divided flow rate, and based on a digital signal of the equally divided flow rate, the flow rate is set downstream of the diverging point.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.